Marc Krikor Kaloustian

Background: Calcium silicate-based sealers have gained in popularity over time due to their physicochemical/biological properties and their possible use with single-cone obturation. The single cone technique is a sealer-based obturation and there is still a knowledge gap regarding the potential impact of the sealer insertion method on the root canal-filling quality. Therefore, the aim of this micro-CT study was to assess the impact of the calcium silicate-based sealer insertion technique on void occurrence and on the sealer extrusion following single-cone obturation. Methods: Thirty-six single-rooted mandibular premolars with one canal were shaped with Reciproc^® R25 (VDW, Munich, Germany) then divided randomly into four groups of nine canals, each depending on the TotalFill^® BC Sealer insertion technique used with single cone obturation: injection in the coronal two-thirds (group A); injection in the coronal two-thirds followed by direct sonic activation (group B); injection in the coronal two-thirds followed by indirect ultrasonic activation on tweezers (group C); sealer applied only on the master-cone (control group D). Samples were then scanned using micro-CT for voids and sealer extrusion calculation. Data were statistically analyzed using v.26 IBM; Results: No statistically significant differences were noted between the four groups in terms of voids; nevertheless, sonic activation (group B) followed by ultrasonic activation on the tweezers (group C) showed the best results (p = 0.066). Group D showed significantly less sealer extrusion when compared with group C (p = 0.044), with no statistically significant differences between groups D, A and B (p > 0.05). Conclusions: Despite no significant differences observed between the different sealer placement techniques, the use of sonic and ultrasonic activation might be promising to reduce void occurrence. Further investigations are needed to demonstrate the potential benefit of calcium silicate-based sealer activation especially in wide and oval root canals in order to improve the quality of the single-cone obturation.

Introduction: Glass ionomer cements (GICs) are commonly used for restorations in primary molars due to their adhesive, hydrophilic, and bioactive properties. However, their low mechanical resistance may limit their use in proximal cavities. Recent advancements in GICs, such as the high viscosity GIC EQUIA Forte®, have improved their mechanical properties. The effect of a Cavo superficial bevel on the mechanical strength of GIC restorations has been previously studied. Objectives: To investigate the effect of a Cavo superficial bevel on fracture resistance and the type of fracture (adhesive, cohesive, or catastrophic) in EQUIA Forte® GIC restorations in primary molars. Methods: A total of 66 standardized proximal cavities were created on 51 temporary molars. The cavities were randomly divided into two groups: group I without a Cavo superficial bevel (n=33) and group II with a 45° Cavo superficial bevel (n=33). The cavities were restored with EQUIA Forte®. The samples were subjected to thermocycling and artificial aging, then, an axial speed loading of 1 mm/min was applied until fracture. Fracture toughness was recorded, and the type of fracture was observed under an optical microscope. A Mann-Whitney U test was used to compare the average fracture resistance between the groups. All tests were two-tailed and the level of significance was set at 5%. Results: The average fracture resistance for group I was (237.57 ± 139.97 N) and for group II was (294.89 ± 171.07 N). There was no statistically significant difference in fracture resistance between the two groups (p>0.05). Mixed fractures were observed in all samples, with adhesive fractures only present in group I and cohesive fractures only present in group II. Conclusions: The Cavo superficial bevel does not significantly affect the fracture resistance of GIC resto rations in primary molars. However, the bevel design may prevent adhesive and catastrophic fractures.

A void-free obturation during root canal treatment on primary teeth is currently very difficult to attain. In this study, the pulpectomy filling abilities of Bio-C Pulpecto (Angelus, Basil, Londrina, Paraná, Brazil) and of zinc oxide eugenol, or “ZOE” (DenPro, Prevest, New York, NY, USA), were compared using several in vitro techniques. Therefore, 30 primary anterior teeth were used in the present in vitro study. Analysis of variance (ANOVA), including a multiple comparison procedure (Holm-Sidak method, Dunn’s Method, or Tukey test), was used. On micro-CT, Bio-C Pulpecto exhibited higher void percentages than did ZOE (10.3 ± 3.8%, and 3.5 ± 1.3%), respectively (p < 0.05). With digital microscopy, higher total void percentages were found in the BC (13.2 ± 26.7%) group compared to the ZOE (2.7 ± 2.8%) group (p < 0.05). With the CLSM, mean tubular penetration depths were higher for Bio-C Pulpecto than for ZOE in all canal thirds (p < 0.05). SEM images demonstrated no tags into dentinal tubules in either group throughout the three thirds. Moreover, higher statistically significant flowability was found for Bio-C (2.657 ± 0.06 mm) compared to ZOE (1.8 ± 0.13 mm) (p < 0.05). The findings of this study indicate that neither ZOE nor Bio-C Pulpecto appears to meet the criteria for an ideal root canal filling paste for primary teeth. This study laid the groundwork for future research by determining how micro-CT, digital microscopy, SEM, and CLSM contribute to our understanding of the filling process of primary teeth. More thorough research on the mechanism of root canal obturation on primary teeth is required to achieve a long-term successful root canal therapy in young children.

Purpose To compare pain perception associated with two computer-controlled local anesthesia devices, the WAND™ STA (Milestone Scientific Inc., Livingston, NJ, USA) and the Calaject (Rønvig dental MFG, Daugaard, Denmark) in young children. Methods A split-mouth randomized clinical trial comprising 30 patients, aged 6–12 years, received randomly, in two separate sessions, a local anesthesia injection in the maxillary using either the wand STA or the Calaject. Pain perception was evaluated using the patient’s heart rate, an 11-point numerical scale (NRS), and the Sound, Eye, and Motor (SEM) body movements. Statistical difference was set at p = 0.05. Repeated measures analysis of variance were conducted to compare the mean pulse for Calaject and STA at different times. It was followed by univariate analysis and Bonferroni multiple comparisons tests. Wilcoxon tests were performed to compare NRS, SEM, and injection duration between Calaject and STA. Results There was no significant statistical difference between Calaject and STA in pulse rate before injection (p = 0.720), during injection (p = 0.767), and after injection (p = 0.757). The mean NRS score was significantly greater with STA in comparison with Calaject (p = 0.017). The mean SEM score was also significantly greater with STA in comparison with Calaject (p = 0.002). However, the mean duration was significantly longer with Calaject (p = 0.001). Conclusions Calaject was more effective than STA in reducing pain perception associated with periapical injection in young children.

Background: To assess the cutting efficiency of two heat-treated endodontic files with a brushing motion in oval-shaped canals. Methods: A total of 10 intact lower molars with a single oval distal canal were selected and randomly divided into two groups according to the system used for shaping: 2Shape and Hyflex CM. The instrumentation was performed in two parts: a first shaping according to the manufacturer’s instructions and final shaping using 5 brushing motions on the distal, lingual, and buccal walls, avoiding the danger zones. Micro computed tomography (micro-CT) scans before and after the brushing motion were superimposed at all three levels: coronal, middle, and apical. Canal changes in buccolingual (ΔBL) and mesiodistal (ΔMD) dimensions were measured. Data were statistically analyzed by repeated-measures analyses of variance and the student t-test (p < 0.05). Results: For ΔMD, no significant difference emerged between the 2Shape and Hyflex CM in the apical and coronal thirds. However, the cutting efficiency was significantly greater with the 2Shape in the middle third (p < 0.05). Regarding ΔBL, no statistically significant difference was detected between 2Shape and Hyflex CM comparing the anatomical thirds, while 2Shape had a significant higher cutting efficiency considering the total BL diameter (p < 0.05). Conclusions: Under the limits of a vitro study, the shaping procedure with 2Shape and brushing motion was more efficient than the Hyflex CM in the midroot levels in terms of ΔMD, and in total canal space for ΔBL. Both files ensured an effective mechanical preparation.

In this study, some physicochemical and antibacterial properties of three root canal filling materials for primary teeth, Calplus “CP” (Prevest DenPro, Lewes, DE, USA), Bio-C Pulpecto “Bio-CP” (Angelus, Basil, Londrina, Paraná, Brazil), and Zinc Oxide and Eugenol “ZOE” (Prevest DenPro, Lewes, DE, USA) were compared. For each material, the pH, solubility, contact angle, and crystalline microstructure under SEM were evaluated. Their antibacterial activity against Enterococcus faecalis was determined through direct tests. The Kruskal–Wallis test was used to analyze the results using a one-way analysis of variance on ranks. All the materials had an alkaline pH at 3, 24, and 72 h, with CalPlus having the highest (p < 0.05). Bio-CP was more soluble during the evaluation period (24 h) than ZOE and CalPlus (p < 0.05). Bio-CP and ZOE demonstrated the creation of crystallite structures on their surfaces after immersion in PBS at 37 °C, whereas CalPlus showed none. The lowest contact angle was observed for Bio-CP (53 ± 1.5°); contact angles of (86 ± 4°) and (96 ± 1°), respectively, were observed after 10 s of the deposition of the water drop for CalPlus and ZOE. In conclusion, according to this study, there is still a need to develop new filling materials for primary teeth. ZOE, CalPlus and Bio-CP demonstrated different physicochemical and antibacterial properties, but none of the materials had optimal properties and could be considered the most suitable filling material for primary teeth pulpectomy. Bioceramics in their current state are not an alternative. The physicochemical and antibacterial properties still need improvement to fit the intricate anatomy of primary teeth.

This study aimed to evaluate the effectiveness of the Endostar REvision system (Poldent, Warsaw, Poland) in the removal of filling materials from oval root canals using sonic irrigation as an additional cleaning method. Thirty human-extracted mandibular premolars with oval canals were prepared using the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland) up to instrument F1 (20/.07), and then filled by the continuous wave vertical compaction technique using pulp canal sealer EWT (Sybron Dental Specialties, Orange, CA, USA). The teeth were randomly divided into two groups (n = 15) according to the instrumentation system and the additional cleaning method, as follows: REvision (30/.08, 25/.06) with EQ-S sonic activation (Meta Biomed, Chungcheongbuk-do, Korea), REvision (30/.08, 25/.06) without additional activation. All specimens were sectioned longitudinally at 3 and 7 mm from the apex, and analyzed using digital microscopy (KEYENCE, Osaka, Japan) to measure the total area of the residual obturation materials, followed by SEM analysis. The data on the percentage of remaining filling material were analyzed by Kruskal–Wallis one-way Analysis of Variance on ranks. None of the retreatment protocols completely removed the filling material from the root canals (p > 0.05); the retreatment technique using sonic activation showed statistically less residual filling materials than the retreatment technique using irrigants without activation at the coronal third (p < 0.05), whilst no significant difference was found between both tested groups at the apical and middle thirds (p > 0.05). The REvision system showed promising results in the removal of filling materials from oval canals.

The purpose is to evaluate canal transportation of a new heat-treated NiTi system, the Endostar E3 Azure operated in continuous rotation or reciprocation. 40 resin blocks were divided into two groups. The first was shaped in continuous rotation while the second in reciprocation. A preoperative and two postoperative images were taken, one after the use of the 20/06 and one after the 25/06. The images were superimposed to determine canal transportation. Time required for canal shaping was recorded. One-sample and student t tests, repeated-measure analyses of variance, univariate analyses and Bonferroni multiple comparisons tests were used for statistical analysis. The significance level was set at p < 0.05. There was no significant difference between continuous and reciprocating motion with the 20/06 and 25/06, respectively, at 1 mm (p = 0.761, p = 0.559), 2 mm (p = 0.584, p = 0.810) and 3 mm (p = 0.651, p = 0.070). The reciprocating motion showed significantly less canal transportation at 5 mm (p = 0.049, p < 0.001) and 7 mm (p < 0.001, p < 0.001) for the 20/06 and 25/0.6. Continuous rotation was more time-consuming than reciprocation (p < 0.001). The Endostar E3 Azure in reciprocation respected the original canal curvature better than in continuous rotation at all levels, and required less time to prepare artificial curved canals. Endodontists should know the shaping abilities of novel heat-treated NiTi files, regarding canal transportation and its relation with the instruments’ motion and apical diameter enlargement.

Aim: To compare two preparation systems and two sonic irrigation devices during the removal of root filling material from oval distal canals of extracted mandibular molars.Methodology: The distal canals in 40 extracted mandibular molars were shaped using the ProTaper Next system (Dentslpy Sirona, Ballaigues, Switzerland), filled with Gutta Percha X2 (Dentsply Sirona), along with AH Plus sealer (Dentsply De Trey, Konstanz, Germany) and randomly divided into two groups (n = 20) according to volume of initial filling, preparation diameter and working length. One group was retreated using the Reciproc system (VDW, Munich, Germany), and the other using the 2Shape system (Micro‐Mega, Besançon, France). A micro‐CT scan was taken after the initial root filling and after retreatment to evaluate the volume of filling material remnants. The teeth were divided into four groups to test the supplementary effect of two sonic irrigation devices on removing filling material: Eddy (VDW) and MM1500 (Micro‐Mega). In the first and second groups, 2Shape was followed subsequently by MM1500 and Eddy; in the third and fourth groups, Reciproc was followed by MM1500 and Eddy. A third micro‐CT was taken to compare the remaining root filling material in all groups. Wilcoxon's signed rank tests, Mann–Whitney and Kruskal–Wallis tests were used for statistical analysis.Results: No significant difference was found for the volume of filling material removed between the Reciproc and 2Shape in the entire canal (P = 0.355). The volume dropped significantly from its initial value after removing the bulk of the root filling by 95.8% (from 4.71 to 0.22 mm³) with the 2Shape (P < 0.001) and by 94.0% (from 5.05 to 0.33 mm³) with the Reciproc (P < 0.001). Sonic activation significantly decreased the residual volume of filling material remnants by 3.21% (P = 0.013) in the first group, 1.38% (P = 0.012) in the second group, 1.83% (P = 0.008) in the third group and 1.83% (P = 0.012) in the fourth group. At the end, the percentage of residual material was not significantly different among the groups in the entire canal (P = 0.163).Conclusion: In the distal oval canals of extracted mandibular molar teeth, there was no significant difference between the 2Shape and Reciproc systems in removing gutta‐percha/sealer. Sonic activation with MM1500 and Eddy significantly improved filling material removal.